When right-clicking an open window, I can choose "Visible on all workspaces". The window is indeed visible on all workspaces; however, if it's a pinned app, it's not registered (in the window list) as open on the other workspaces. The button indicates that the app is not open on the other workspaces even though it definitely is. Pressing the app's icon will open a new window. (Closing the new window will "deactivate" the pinned app again, even though the "all-workspaces" window is still open).
When right-clicking an open window, I can choose "Visible on all workspaces". The window is indeed visible on all workspaces; however, if it's a pinned app, it's not registered (in the window list) as open on the other workspaces. The button indicates that the app is not open on the other workspaces even though it definitely is. Pressing the app's icon will open a new window. (Closing the new window will "deactivate" the pinned app again, even though the "all-workspaces" window is still open).